Velcro hook and loop fasteners are widely used for attaching one object to another. These devices are made up of two mating tapes, a hook tape that has a large number of minute flexible hooks woven into a nylon fabric substrate and a loop tape having loops woven into a second nylon substrate. When the two tapes are pressed together, the hooks engage the loops, forming an adjustable, highly secure, and jam-proof closure. To reopen, the tapes are simply pulled apart.
Many applications would exist for such hook and loop tapes for the purpose of displaying designs or other graphic material on the back, smooth side of the tape. For example, one tape could be secured to a chart board with its hook or loop side out, and a mating piece of the other tape with graphics on its back side could be removably attached to the first side so as to enable the graphics to be moved to different locations along the chart. Company logos, advertising material, and the like could also be displayed on the tape. Such applications would be facilitated by the availability of an effective process for printing of graphics onto the back side of the hook or loop tape.
Substantial difficulty has been encountered in printing of multicolor graphic materials onto the backs of hook and loop tapes owing to the surface structure of the tape. The back or smooth side of the tapes has an elastomeric binder coat applied over a woven nylon substrate having hooks or loops woven into the substrate. The binder coat locks the hooks or loops into the ground weave and helps to prevent the tape from unravelling when cut. This coating interferes with the use of screen printing processes in that the tape material will not accept many of the dyes used for screen printing, causing the design material to run together or peel. In particular, application of more than two colors by screen printing has presented such problems. Sublimation heat-transfer printing processes have also been attempted for applying multicolor materials to hook or loop tapes, but with little success. Prints applied by sublimation heat transfer processes have been characterized by defects such as the appearance of ghost images and a haziness or lack of sharpness. Difficulties in printing of multicolor designs on Velcro material may also be attributed to movement of the fabric when opening or closing a heat transfer press because of the presence of hooks or loops in the material. In carrying out these processes, much material may be wasted owing to the poor quality, unusable, or marginal results obtained. Costs are increased due to the large amount of scrap generated and the amount of time consumed.